Re: `match-data' set improperly

[Richard Stallman]

    I think match-beginning, match-end, and string-match should signal an error
    if match-data is nil.

This is the sort of thing that is really more risky than it looks like.
You can convince yourself that nothing will break, and if it is, it had
a bug anyway.  But the end result is that it makes for more work.

This might be a change for the better in the long term, despite that;
but we have enough work now, so let's not make more.

Meanwhile, we should really focus on changes that make Emacs more powerful
for users, not on elegance of the programming system.